I bought the Ferraro book "Programmer's Guide to the EGA, VGA, Super VGA Cards", Abrash's "Graphics Programming Black Book", and had an ASCII reference to the VGA card from IBM back in my VGA programming days.

But even with all that, they still didn't have as many details as this PDF does!

This is such a great reference. Some things about the card I didn't understand ~14 years ago finally make sense now. Thank you!